So I finally managed to get the install to function by bypassing the framework-finding code and just hardcoding the locations of the frameworks into the script. Then had to fix some of the framework directory structures. App opens, but I get an unresponsive black window. Console is filled with

Getting some of the same problems when trying to compile MegaMod 0.8.0 rev7; not sure if it's my computer in particular or 10.13 in general.

Hadn't really looked at MegaMod before, but it seems to include most of the changes I was trying to make, so I suppose I don't really need to build from source at this point. There's one new feature I'd like to see, but I'll request that in the appropriate thread.